Media mobility unit (mmu) and methods of use thereof

ABSTRACT

In one embodiment, a media mobility unit includes a media cartridge holding portion configured to simultaneously store multiple media cartridges, a sensing mechanism for sensing at least an approximate location of the holding portion in relation to other objects, a drive mechanism for moving the holding portion from a source media library to a destination media library, and a power source electrically coupled to at least one of the sensing mechanism and the drive mechanism for providing current to the at least one of the drive mechanism and the sensing mechanism. In another embodiment, a method for transporting a media cartridge includes receiving one or more media cartridges from a source media library, storing the one or more media cartridges in a holding portion of a media mobility unit, sensing at least an approximate location of the media mobility unit, and transporting the one or more media cartridges to a destination media library. Additional embodiments are also presented.

RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 13/105,844, filed May 11, 2011, which is herein incorporated byreference.

BACKGROUND

The present invention relates to data storage systems using mediacartridges and media libraries, and more particularly, to a mediamobility unit for moving media cartridges between media libraries.

Media libraries serve as practical solutions to the massive data storageand redundancy requirements of modern computing operations. Medialibraries host a finite number of media volumes for storing data, andtypically these volumes are classified as tape or disk, depending on thedata storage format. In order to meet access and redundancyrequirements, many operations employ multiple libraries at multipleaccess points. When using a plurality of access points without universalor shared accessibility, physical volumes are occasionally unmountedfrom one media library and mounted to another in order to provide accessto the requested volume. In addition, new volumes may be occasionally beused to replace full volumes and permit storage of additional new data.

Typically, these physical movements are performed by human techniciansmanually entering a command to unmount a source volume from a sourcelibrary, receiving the requested volume from the source library,carrying the source volume to a destination library, placing the sourcevolume in a destination library receptacle, and entering a command tomount the source volume in the destination library.

Some recent approaches have endeavored to automate the process ofunmounting, receiving, transferring, and mounting volumes from one medialibrary to another by way of mechanical arms, tracks, and/or rails totransfer volumes between two libraries. In these approaches, however,media libraries must be in sufficiently close physical proximity suchthat the arm, track, and/or rails may span the distance between sourceand destination media libraries. This proximity requirement placesphysical limits on the arrangement of media libraries in a physicalspace. In addition, since each library must be attached to an arm,track, or railing as well as a mechanism for moving media along the arm,track, or railing, it can be very expensive to replace existing medialibraries with those having the requisite mobility mechanisms. Even ifmedia libraries may be retrofit with such mobility devices, interfacingmultiple libraries becomes increasingly problematic as the number oflibraries increases, again due in large part to spatial limitations.

However, as computational resources and data security continue to accruesignificance in this information age, current approaches to efficientlymove media volumes between media libraries is becoming increasinglyunsuitable for evolving performance requirements. Therefore, it would bea useful endeavor to develop a system and method for providing mobilityto a network of media libraries without incurring the enormous cost ofreplacing current libraries or the spatial limitations imposed bypermanent tracks, arms, and/or rails connecting media libraries inphysical proximity. Furthermore, it would be advantageous to eliminatethe spatial limitations and proximity requirements of currentlyenvisioned media mobility systems.

BRIEF SUMMARY

According to one embodiment, a data storage system includes a sourcemedia library configured to send a message to a destination medialibrary when a media cartridge from the source media library is sent tothe destination media library using a media mobility unit (MMU)comprising a media cartridge holding portion for storing mediacartridges, wherein the source media library is configured to receive amessage from the destination media library when the destination medialibrary receives the media cartridge sent from the source media libraryto the destination media library using the MMU.

In another embodiment, a data storage system includes a destinationmedia library configured to receive a message from a source medialibrary when a media cartridge from the source media library is sent tothe destination media library using a media mobility unit (MMU)comprising a media cartridge holding portion for storing mediacartridges, wherein the destination media library is configured to senda message to the source media library when the destination media libraryreceives the media cartridge from the source media library.

In another embodiment, a MMU includes a media cartridge holding portionconfigured to simultaneously store multiple media cartridges, a sensingmechanism for sensing at least an approximate location of the holdingportion in relation to other objects, a drive mechanism for moving theholding portion from a source media library to a destination medialibrary, and a power source electrically coupled to at least one of thesensing mechanism and the drive mechanism for providing current to theat least one of the drive mechanism and the sensing mechanism.

In yet another embodiment, a method for transporting a media cartridgeincludes receiving one or more media cartridges from a source medialibrary, storing the one or more media cartridges in a MMU, sensing atleast an approximate location of the MMU, and transporting the one ormore media cartridges to a destination media library.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrates by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a schematic of a media mobility unit from a sideview, according to one embodiment.

FIG. 2 illustrates a schematic of a media mobility unit from a distalview, according to one embodiment.

FIG. 3 illustrates a schematic of a media library from a front view,according to one embodiment.

FIG. 4 illustrates a schematic of a media mobility unit docked with amedia library from a side view, according to one embodiment.

FIG. 5 illustrates a diagrammatic layout of a media library beingserviced by a media mobility unit, according to one embodiment of agrid-based location system (GBLS).

FIG. 6 is a flow diagram of a method, according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferents unless otherwise specified.

According to one general embodiment, a data storage system includes asource media library configured to send a message to a destination medialibrary when a media cartridge from the source media library is sent tothe destination media library using a media mobility unit (MMU)comprising a media cartridge holding portion for storing mediacartridges, wherein the source media library is configured to receive amessage from the destination media library when the destination medialibrary receives the media cartridge sent from the source media libraryto the destination media library using the MMU.

In another general embodiment, a data storage system includes adestination media library configured to receive a message from a sourcemedia library when a media cartridge from the source media library issent to the destination media library using a media mobility unit (MMU)comprising a media cartridge holding portion for storing mediacartridges, wherein the destination media library is configured to senda message to the source media library when the destination media libraryreceives the media cartridge from the source media library.

In another general embodiment, a MMU includes a media cartridge holdingportion for storing media cartridges, a sensing mechanism for sensing atleast an approximate location of the holding portion in relation toother objects, a drive mechanism for moving the holding portion from asource media library to a destination media library, and a power sourceelectrically coupled to at least one of the sensing mechanism and thedrive mechanism for providing current to the at least one of the drivemechanism and the sensing mechanism.

In yet another general embodiment, a method for transporting a mediacartridge includes receiving one or more media cartridges from a sourcemedia library, storing the one or more media cartridges in a MMU,sensing at least an approximate location of the MMU, and transportingthe one or more media cartridges to a destination media library.

Referring now to the figures, FIG. 1 shows a schematic of a mediamobility unit (MMU) 100 from a side view, according to one embodiment.As shown, the MMU 100 includes three portions: a power source portion102, a connecting portion 104, and a cartridge holding portion 106. TheMMU 100 also includes a mechanism for moving the unit, shown as a pairof front drive wheels 118 (only one wheel is visible due to the drawingangle) capable of providing forward or reverse motion to the unitindependently to facilitate motion, turning, and pivoting, and a singlecastor wheel 120 adapted for providing support to the MMU 100. Inanother embodiment, the drive wheels 118 may each provide a forward orreverse motion to the MMU 100 while the rear wheel 120 provides adirection. In yet another embodiment, there may be more than one rearwheel 120, which may or may not provide direction to the MMU 100.

With continuing reference to FIG. 1, the power source portion 102 mayinclude a rechargeable power source, such as a rechargeable battery, andmay be adapted for being recharged at designated stations, such as whilebeing docked at a media library. Furthermore, the power source portion102 may include additional components, such as a position sensor orlaser reader 124, swiveling wheels 120, etc. In one embodiment, thepower source portion 102 may include non-rechargeable batteries that arereplaceable, a power source that operates from contact with a powersupply (such as one used for light rail train engines), or any otherpower source as would be understood by one of skill in the art uponreading the present descriptions.

In one embodiment, a laser reader 124 extends proximally from the rearside of the MMU 100. The laser reader 124, as shown, is adapted forreading one or more barcodes 122 which may be located at positions alongthe floor, on walls, on the ceiling, in a grid, or anywhere else thatthe laser reader 124 is capable of reading them as the MMU 100 passesby. The barcodes 122 may have any dimension and may comprise any patternadapted for being recognized by the laser reader 124. In one embodiment,the bar codes 122 may be positioned at each floor tile (such as floortiles measuring 24 in.×24 in. or any other dimension) such that movementof the MMU 100 is detectable at each floor tile. Of course, many otherbarcode 122 positions are possible, and the positioning of the barcodes122 is not meant to be limited in any way by this description.

In more embodiments, more than one laser reader 124 may be used, andeach laser reader 124 may be positioned at any location on the MMU 100that facilitates the reading of the barcodes 122, according to variousembodiments, such as on the media cartridge portion 106, on theconnecting portion 104, on the bottom, on the top, on one or more sides,etc. As the MMU 100 travels from a source media library to a destinationmedia library, the barcodes 122 may be read by the laser reader 124 suchthat a current position of the MMU 100 is detectable during the transit,such that proper retrieval and delivery of media cartridges may beaccomplished.

In another approach, the laser reader 124 may function as a positionsensor to determine the position of the MMU 100. Of course, alternateembodiments may utilize similar variations of a barcode and laser readerto navigate between and identify various media libraries in a storagesystem. Furthermore, alternate embodiments may utilize similarvariations of a barcode and laser reader to determine the position ofthe MMU 100.

in another embodiment, the MMU 100 may comprise a radio frequencyidentification (RFID) device to determine positional information of theMMU 100, such as an RFID reader. In this embodiment, RFID tags may bepositioned throughout a storage system such that each media library isrepresented, and paths between the media libraries are designated by theRFID tags.

According to one embodiment, the swivel wheels 120 protrude from thebottom of the MMU 100 near the rear and provide pivoting capability andlateral mobility to the MMU 100. Any type of pivoting wheel may be used,such as a castor wheel, a wheel coupled to a swiveling base, ballbearings, etc.

Referring still to FIG. 1, the cartridge holding portion 106 may belocated at a distal end of the MMU 100 and coupled to the power sourceportion 102 via the connecting portion 104. In some embodiments, aconnecting portion 104 is not used when the power source portion 102connects to the cartridge holding portion 106 directly. The cartridgeholding portion 106 may further be connected to the drive wheels 118,which may confer longitudinal mobility to the MMU 100 by driving italong a surface upon receiving a request to retrieve or store a mediacartridge or move to a new location in a grid-based location system(GBLS).

The cartridge holding portion 106 additionally includes severalcomponents adapted for conferring various capabilities to the MMU 100.

In one approach, the cartridge holding portion 106 includes sensors. Forexample, one or more proximity sensors 110 may be adapted for conveyinginformation about proximity of nearby objects to the MMU 100 as ittravels between media libraries. In another example, one or morefiducial sensors 108 may be coupled to the cartridge holding portion 106that may be adapted for communicating alignment information as the MMU100 attempts to interface with a media library, which is equipped with acorresponding sensor or alignment mechanism.

Additionally, the cartridge holding portion 106 may comprise lockingpins 116 located at a lower distal end of the MMU 100 and adapted forengaging locking pin slots of media libraries upon docking with themedia library in order to avoid unexpected or undesirable motion duringa media transfer operation. Alternatively, the cartridge holding portion106 may include locking pin slots 116 adapted for receiving locking pinsdeployed from a media library upon docking the MMU 100 with the medialibrary in order to avoid unexpected or undesirable motion during amedia transfer operation. In either case, the locking pins and lockingpin slots may be constructed and operate in any manner as known to onehaving ordinary skill in the art.

Furthermore, in one embodiment, there may be a power charger 114 locatedon a distal end of the MMU 100 and adapted for charging the power sourceportion 102 of the MMU 100 upon docking with a media library.

With continuing reference to FIG. 1, the cartridge holding portion 106may include a communication input/output (I/O) 112 for receiving inputdata from a media library and delivering output data to a media library.This I/O connection 112 may be used for transferring instructions from asource library to the MMU 100 that instructs the MMU 100 to travel to adestination library located remotely from the source media library tomove a media cartridge therebetween. Of course, any other instructionsmay be provided to the MMU 100 as would be understood by one of skill inthe art upon reading the present descriptions. The I/O connection may beof any type as would be known in the art.

According to one approach, the source media library (such as from alibrary control manager) may send a message to the destination medialibrary and/or some other system (such as a storage controller) that thesource media library is sending a media cartridge to the destinationmedia library. When the media cartridge is received by the destinationmedia library, the destination media library may send a message to thesource media library and/or some other system that the media cartridgefrom the source media library was received at the destination medialibrary. This ensures that there is a “handshake” between the medialibraries such that a media cartridge in transit is not lost during thetransportation thereof. Otherwise, once the media cartridge was sentfrom the source media library, there would be no evidence of itsintended delivery or that it left the source media library. Of course,other methods may be used to ensure that media cartridge visibility andaccountability is maintained during the transportation process, as wouldbe understood by one of skill in the art upon reading the presentdescriptions.

In some further approaches, there may be a time period associated withwhen the media cartridge is sent from the source media library and whenit is delivered to the destination media library such that if themessage indicating the media cartridge's arrival is not received by thesource media library and/or some other system prior to the expiration ofthis time period, an alert may be issued that a problem has arisen inthe transportation of the media cartridge. In response to this alert, atechnician, administrator, or some other suitable person may determinewhat has caused the delay in the delivery of the media cartridge.

According to one embodiment, the source media library may be configuredto send a message to a destination media library when a media cartridgefrom the source media library is sent to the destination media library,and the source media library may be configured to receive a message fromthe destination media library when the destination media libraryreceives the media cartridge from the source media library.

In another embodiment, the destination media library may be configuredto receive a message from a source media library when a media cartridgefrom the source media library is sent to the destination media library,and the destination media library may be configured to send a message tothe source media library when the destination media library receives themedia cartridge from the source media library.

In one approach, the cartridge holding portion 106 may include one ormore cartridge storage devices. The cartridge storage devices include aplurality of slots capable of securely holding media volumes during MMU100 motion between media libraries, as will be described in reference toFIG. 2.

Referring again to FIG. 1, according to one embodiment, a MMU 100comprises a media cartridge holding portion 106 for storing mediacartridges, at least one sensing mechanism 108 and/or 110 for sensing atleast an approximate location of the holding portion 106 in relation toother objects, a drive mechanism 118 for moving the holding portion 106from a source media library to a destination media library, and a powersource 102 electrically coupled to at least one of the sensing mechanism108 and/or 110 and the drive mechanism 118 for providing current to theat least one of the drive mechanism 118 and the sensing mechanism 108and/or 110. Of course, power may also be supplied to other components ofthe MMU 100, and other components may exist, as described previously.

Referring now to FIG. 2, in one embodiment the cartridge holding portion106 of the MMU may have the capability to hold various types of mediacartridges, such as magnetic tape cartridges (e.g., linear tape-open(LTO) compatible tape cartridges and/or 3592 format tape cartridges,etc.), disc cartridges, etc. In one approach, the cartridge holdingportion 106 may include more than one configuration of cartridge storagedevices 202 and/or 204. As shown, the cartridge holding portion 106includes a plurality of storage slots 206, each capable of storing amedia volume from a media library. In the embodiment shown in FIG. 2,the cartridge holding portion 106 is depicted with a first cartridgeholder 202 and a second cartridge holder 204. While this embodimentdepicts a cartridge holding portion 106 with two types of cartridgeholders, alternative embodiments may hold any number of cartridgeholders, limited only by the physical dimensions and dockingcapabilities of the associated media libraries.

In operation, the cartridge storage devices 202 and/or 204 are adaptedfor interfacing with a picker of a media library in order to transfermedia cartridges between the MMU and the media library. In this manner,the MMU may securely store the retrieved volume(s) in the cartridgestorage device 202 and/or 204, retrieve the stored volume(s) uponarrival at a destination library, and deliver the retrieved volume(s) toa destination media library, in one approach.

Referring now to FIG. 3, a media library 300 is shown, according to oneembodiment. As depicted, the media library 300 includes a housing 302,an operator panel 304, an I/O station 306, and a docking station 312.The docking station 312 may further include one or more doors 308, and afiducial 310. In operation, the docking station 312 may serve as aninterface point for one or more MMUs servicing a GBLS with associatedmedia libraries 300.

In another embodiment, and with continuing reference to FIG. 3, the oneor more doors 308 may be configured to open via spring-loading or otherautomated opening mechanisms as known to one having ordinary skill inthe art. Other embodiments may be adapted to automatically trigger theopening mechanism and open the doors 308 when a MMU begins to interfacewith the docking station 312 of the media library 300. In addition, thedoors 308 may similarly be configured to automatically close when a MMUdetaches from the docking station 312 of the media library 300.Alternatively, the doors 308 may be triggered to open upon successfulengaging of the locking pins 116 with corresponding locking pin slots,etc.

Referring now to FIG. 4, a MMU 100 is shown interfacing with a dockingstation 312 of a media library 300, according to one embodiment. Asshown, the MMU 100 is docking with the media library 300 at the levelwhere the doors are located, such that an operator would still be ableto access the operator panel 304. Of course, any configuration may beused as would be understood by one of skill in the art upon reading thepresent descriptions.

Referring now to FIG. 5, a GBLS 500 and corresponding MMU 100 fortransporting media cartridges between a source and destination medialibrary are shown, according to one embodiment. As shown, the GBLS 500includes a plurality of indicators 506 on one or more surfaces, theplurality of indicators 506 being positioned to be readable by a deviceon the MMU 100. In one embodiment, the indicators 506 may be barcodes,and the device for reading the indicators 506 may be a barcode reader.In another embodiment, the indicators 506 may be RFID tags, and thedevice for reading the indicators 506 may be a RFID reader. Of course,any other indicator and device capable of reading the indicators may beused as one of skill in the art would understand upon reading thepresent descriptions.

The indicators 506 are positioned in pathways 502 between a plurality ofmedia libraries 300, each media library having an associated dockingstation 312 and an indicator 508 designating the position of the dockingstation 312. In operation, the MMU 100 may travel along a plurality ofpathways 502 from a source media library to a destination media library,detect a proximate media library 300 via a proximity sensor, read amedia barcode 506, and identify whether the particular library is theappropriate destination by comparing an observed barcode value to arequested barcode value. When the MMU 100 identifies a library as theappropriate destination, it may furthermore initiate a docking sequencewith the docking station 312 of the destination library.

Alternatively, in another embodiment, the MMU 100 may be provided with aset of addresses for each media library 300 in the GBLS 500 andadditionally with appropriate travel pathways 502 for traversing theGBLS 500 from library to library.

In still another embodiment, the MMU may be provided with optimizationalgorithms such as machine-learning to maximize efficiency of mediamobility according to one or more user-defined variables such as traveltime, travel distance, number of pickups or deliveries, etc. In such anapproach, the MMU 100 may calculate an optimum travel route according touser preferences and as understood by one having ordinary skill in theart.

Furthermore, in yet another embodiment, the MMU 100 may record transitdata in real-time as it mobilizes media between libraries. Such data mayinclude travel time, travel distance, number of receipts or deliveries,etc. Upon a request to move media between libraries, the MMU 100 maycalculate an optimum travel protocol by comparing real-time data tooptimization criteria, including user-defined criteria.

In some approaches, the MMU 100 may encounter one or more obstacles 504during transit between media libraries 300. To prevent collisions, theMMU 100 may detect such obstacles via a proximity sensor or may beinstructed of the obstacle's presence by a source media library or auser, and in order to maintain operations, the MMU 100 may be instructedto return to a previous location, calculate a new route, and travelalong the new route to move to the destination library. Furthermore, theMMU 100 may include obstacle locations as a factor when calculating anoptimum travel protocol in order to avoid repeated collisions,backtracking, and generally to improve mobility and efficiency.

As envisioned, a GBLS 500 may include any number of media libraries 300and MMUs 100 capable of being interfaced in a network environment andhoused within a storage facility. The media libraries 300 may benetworked in any manner as understood by one having ordinary skill inthe art.

Furthermore, in one embodiment, a MMU 100 may sense at least anapproximate location of the MMU 100 in relation to the pathways 502 andlibraries 300 and transport one or more media cartridges to adestination media library.

In another embodiment, the MMU 100 may recharge a power source of theMMU 100 when the MMU 100 is docked at either of the source media libraryand the destination media library.

Also, in some embodiments, transporting the one or more media cartridgesto the destination media library may comprise using a laser barcodereader to read a first barcode (indicator 506) of a plurality ofbarcodes 506 positioned on one or more surfaces in the grid system 500at least between a source media library and a destination media library(any of media libraries 300). Each of the plurality of barcodesindicates at least an approximate location of the MMU 100 in the gridsystem 500, and the MMU 100 is moved from a first barcode in a directionfor causing the MMU 100 to arrive at a second barcode of the pluralityof barcodes positioned in the grid system 500, the direction being basedon at least one of: a location of the first barcode and a location ofthe destination media library, and using the laser barcode reader toread the second barcode.

In more embodiments, sensing the at least an approximate location of theMMU 100 comprises at least one of sensing objects near the MMU 100,sensing when the holding portion is aligned with a cartridge holder ofthe source media library, and sensing a position of the MMU 100 in theGBLS 500.

Sensing the position of the MMU 100 in the GBLS 500 comprises at leastone of: reading barcodes positioned on one or more surfaces in the GBLS500 to determine the position of the MMU 100 in the GBLS 500 and using aRFID device to sense RFID devices positioned in the GBLS 500 todetermine the position of the MMU 100 in the GBLS 500. In oneembodiment, the first RFID device may comprise a RFID reader capable ofreading RFID tags positioned in the GBLS 500 at least between the sourcemedia library and the destination media library for indicating theposition of the MMU 100 in the GBLS 500.

According to one embodiment, the source media library may be configuredto send a message to a destination media library when a media cartridgefrom the source media library is sent to the destination media library,and the source media library may be configured to receive a message fromthe destination media library when the destination media libraryreceives the media cartridge from the source media library.

In another embodiment, the destination media library may be configuredto receive a message from a source media library when a media cartridgefrom the source media library is sent to the destination media library,and the destination media library may be configured to send a message tothe source media library when the destination media library receives themedia cartridge from the source media library.

Referring now to FIG. 6, a method for using one or more MMUs 100 in aGBLS 500 is shown, according to one embodiment. The method 600 may becarried out in any desired environment and may make use of anycomponents, including those shown in FIGS. 1-5, among others.

In operation 602, one or more media cartridges are received from asource media library. The source media library may include a mediacartridge, such as a tape cartridge, that is to be transported to adestination library.

In operation 604, the one or more media cartridges are stored in aholding portion of a MMU. The holding portion of the MMU may hold othermedia cartridges for transport, or may hold other types of media to betransported, in various embodiments. In one approach, this may beaccomplished using a picker of the source media library to capture themedia cartridges from the media library and placing them in the holdingportion of the MMU, as would be apparent to one of skill upon readingthe present descriptions.

In operation 606, at least an approximate location of the MMU is sensed.The approximate location may be sensed periodically, when encounteringindicators, or in any other way as would be understood by one of skillin the art upon reading the present descriptions.

In one embodiment, the approximate location may be sensed based onsensing objects near the MMU, sensing when the holding portion isaligned with a cartridge holder of the source media library, and sensinga position of the MMU in a grid system.

In a further embodiment, sensing the position of the MMU in the gridsystem may comprise at least one of: reading barcodes positioned on oneor more surfaces in the grid system to determine the position of the MMUin the grid system, and using a first RFID device to sense RFID devicespositioned in the grid system to determine the position of the MMU inthe grid system.

Additionally, in some approaches, the first RFID device may comprise aRFID reader capable of reading RFID tags positioned in the grid systemat least between the source media library and the destination medialibrary for indicating the position of the MMU in the grid system.

In operation 608, the one or more MMUs are transported to a destinationmedia library located remotely from the source media library where theone or more media cartridges may be delivered to the destination medialibrary.

According to one embodiment, a laser barcode reader may be used to reada first barcode of a plurality of barcodes positioned on one or moresurfaces in a grid system at least between the source media library andthe destination media library, wherein each of the plurality of barcodesindicates at least an approximate location of the MMU in the gridsystem. Also, the MMU may be moved from the first barcode in a directionfor causing the MMU to arrive at a second barcode of the plurality ofbarcodes positioned in the grid system, the direction being based on atleast one of: a location of the first barcode and a location of thedestination media library. Furthermore, the laser barcode reader may beused to read the second barcode to repeat the process.

In operation 610, the one or more media cartridges are transferred fromthe holding portion of the MMU to the destination media library. In oneapproach, this may be accomplished using a picker of the destinationmedia library to capture the media cartridges from the holding portionof the MMU and placing them in the media library, as would be apparentto one of skill upon reading the present descriptions.

According to one embodiment, the MMU may comprise a media cartridgeholding portion for storing the one or more media cartridges, a sensingmechanism for sensing at least an approximate location of the MMU inrelation to other objects, a drive mechanism for moving the MMU from thesource media library to the destination media library, and a powersource electrically coupled to at least one of the sensing mechanism andthe drive mechanism for providing current to the at least one of thedrive mechanism and the sensing mechanism.

In some embodiments, the power source may be recharged when the MMU isdocked at either of the source media library and the destination medialibrary.

In one embodiment, a data storage system comprises a MMU comprising amedia cartridge holding portion for storing media cartridges, and asource media library. The source media library is configured to send amessage to a destination media library when a media cartridge from thesource media library is sent to the destination media library, and thesource media library is configured to receive a message from thedestination media library when the destination media library receivesthe media cartridge from the source media library.

In another embodiment, a data storage system comprises a MMU comprisinga media cartridge holding portion for storing media cartridges, and adestination media library. The destination media library is configuredto receive a message from a source media library when a media cartridgefrom the source media library is sent to the destination media library,and the destination media library is configured to send a message to thesource media library when the destination media library receives themedia cartridge from the source media library.

The data storage system may further comprise either or both of thedestination media library and the source media library, wherein thedestination media library may be located remotely from the source medialibrary, according to various embodiments.

In another embodiment, the data storage system may further comprise theMMU and a grid system at least between the source media library and thedestination media library comprising a plurality of indicators on one ormore surfaces. The MMU may comprise a drive mechanism for moving theholding portion from the source media library to the destination medialibrary, at least one proximity sensor for sensing objects near the MMU,a fiducial sensor for aligning the holding portion with a cartridgeholder of at least one of the source media library and the destinationmedia library, and at least one position reading mechanism for sensingthe plurality of indicators for indicating at least an approximatelocation of the MMU in the grid system, wherein the MMU uses the atleast the approximate location to determine a next movement of the MMU.

In a further embodiment, the MMU may further comprise a power sourceelectrically coupled to the at least one proximity sensor, the fiducialsensor, the at least one position reading mechanism, and the drivemechanism for providing current to the at least one proximity sensor,the fiducial sensor, the at least one position reading mechanism, andthe drive mechanism. The drive mechanism may comprise a motor forproviding rotation to each of a first drive wheel and a second drivewheel independently, the first and second drive wheels positionedopposite each other near the holding portion for propelling the MMU, anda swiveling caster wheel for allowing directional changes of the MMUpositioned to provide stability to the MMU. The plurality of indicatorsmay comprise a plurality of barcodes and the at least one positionreading mechanism may comprise at least one laser barcode reader forreading the plurality of barcodes positioned on the one or more surfacesin the grid system.

In another embodiment, a media cartridge mobility system includes a gridsystem (such as that described in relation to FIG. 5) at least between asource media library and a destination media library located remotelyfrom the source media library. The grid system comprises a plurality ofindicators 506 (which may be barcodes, RFID devices, etc.) on one ormore surfaces, the plurality of indicators being positioned to bereadable by a position reading mechanism on the MMU (such as a barcodereader, an RFID reader, etc.). The system also includes a MMU (such asthat described in relation to FIG. 1), the MMU including a mediacartridge holding portion for storing media cartridges, a drivemechanism for moving the holding portion from a source media library toa destination media library, at least one proximity sensor for sensingobjects near the MMU, a fiducial sensor for aligning the holding portionwith a cartridge holder of at least one of the source media library andthe destination media library, at least one position reading mechanism(such as a laser barcode reader, an RFID reader, etc.) for sensing theplurality of indicators positioned on the one or more surfaces in thegrid system for indicating at least an approximate location of the MMUin the grid system, wherein the MMU uses the at least the approximatelocation to determine a next movement of the MMU, a power sourceelectrically coupled to the at least one proximity sensor, the fiducialsensor, the at least one position reading mechanism, and the drivemechanism for providing current to the at least one proximity sensor,the fiducial sensor, the at least one position reading mechanism, andthe drive mechanism. The drive mechanism includes: a motor for providingrotation to each of a first drive wheel and a second drive wheelindependently, the first and second drive wheels positioned oppositeeach other near the holding portion for propelling the MMU, and aswiveling caster wheel for allowing directional changes of the MMUpositioned to provide stability to the MMU.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. A data storage system, comprising: a source medialibrary configured to send a message to a destination media library whena media cartridge from the source media library is sent to thedestination media library using a media mobility unit (MMU) comprising amedia cartridge holding portion for storing media cartridges, whereinthe source media library is configured to receive a message from thedestination media library when the destination media library receivesthe media cartridge sent from the source media library to thedestination media library using the MMU.
 2. The data storage system asrecited in claim 1, further comprising: the MMU, wherein the MMU furthercomprises: a drive mechanism for moving the holding portion from thesource media library to the destination media library; and a fiducialsensor for aligning the holding portion with a cartridge holder of atleast one of the source media library and the destination media library.3. The data storage system as recited in claim 2, wherein the MMUfurther comprises a rechargeable battery for providing electricity tothe drive mechanism, the battery being adapted for recharging when theMMU is docked at a media library.
 4. The data storage system as recitedin claim 1, further comprising: the MMU, wherein the MMU furthercomprises: a drive mechanism for moving the holding portion from thesource media library to the destination media library; and at least oneposition reading mechanism for sensing indicators that indicate at leastan approximate location of the MMU in a grid system, wherein the MMUuses the at least the approximate location to determine a next movementof the MMU, wherein the MMU is configured to propel itself between thesource and destination media libraries
 5. The data storage system asrecited in claim 1, wherein the source media library is configured todetermine, using the message received thereby, that the destinationmedia library received the media cartridge:
 6. A data storage system,comprising: a destination media library configured to receive a messagefrom a source media library when a media cartridge from the source medialibrary is sent to the destination media library using a media mobilityunit (MMU) comprising a media cartridge holding portion for storingmedia cartridges, wherein the destination media library is configured tosend a message to the source media library when the destination medialibrary receives the media cartridge from the source media library, themessage indicating that the destination media library received the mediacartridge.
 7. The data storage system as recited in claim 6, furthercomprising: the MMU, wherein the MMU further comprises: a drivemechanism for moving the holding portion from the source media libraryto the destination media library; a fiducial sensor for aligning theholding portion with a cartridge holder of at least one of the sourcemedia library and the destination media library; and at least oneposition reading mechanism for sensing the plurality of indicators forindicating at least an approximate location of the MMU in the gridsystem, wherein the MMU uses the at least the approximate location todetermine a next movement of the MMU, wherein the MMU is configured topropel itself between the source and destination media libraries.
 8. Thedata storage system as recited in claim 6, further comprising: the MMU,wherein the MMU further comprises: a drive mechanism for moving theholding portion from the source media library to the destination medialibrary; and a fiducial sensor for aligning the holding portion with acartridge holder of at least one of the source media library and thedestination media library.
 9. The data storage system as recited inclaim 8, wherein the MMU further comprises a rechargeable battery forproviding electricity to the drive mechanism, the battery being adaptedfor recharging when the MMU is docked at a media library.
 10. The datastorage system as recited in claim 6, further comprising: the MMU,wherein the MMU further comprises: a drive mechanism for moving theholding portion from the source media library to the destination medialibrary; and at least one position reading mechanism for sensingindicators that indicate at least an approximate location of the MMU ina grid system, wherein the MMU uses the at least the approximatelocation to determine a next movement of the MMU, wherein the MMU isconfigured to propel itself between the source and destination medialibraries
 11. A media mobility unit (MMU), comprising: a media cartridgeholding portion configured to simultaneously store multiple mediacartridges; a sensing mechanism for sensing at least an approximatelocation of the holding portion in relation to other objects; a drivemechanism for moving the holding portion from a source media library toa destination media library located remotely from the source medialibrary; and a power source electrically coupled to at least one of thesensing mechanism and the drive mechanism for providing current to theat least one of the drive mechanism and the sensing mechanism.
 12. TheMMU as recited in claim 11, wherein the sensing mechanism comprises atleast one of: a proximity sensor for sensing objects near the MMU; afiducial sensor for aligning the holding portion with a cartridge holderof a media library; and a position reading mechanism for determining aposition of the MMU.
 13. The MMU as recited in claim 12, wherein thesensing mechanism comprises a position reading mechanism, the positionreading mechanism comprising a laser barcode reader for reading aplurality of barcodes positioned on one or more surfaces.
 14. The MMU asrecited in claim 13, wherein the plurality of barcodes are positioned ina grid system at least between the source media library and thedestination media library for indicating at least the approximatelocation of the MMU in the grid system, wherein the MMU uses the atleast the approximate location to determine a next movement of the MMU.15. The MMU as recited in claim 11, wherein the sensing mechanismcomprises a position reading mechanism, the position reading mechanismcomprising a radio frequency identification (RFID) device.
 16. The MMUas recited in claim 15, wherein the RFID device comprises a RFID readercapable of reading RFID tags positioned in a grid system at leastbetween the source media library and the destination media library forindicating at least the approximate location of the MMU in the gridsystem, wherein the MMU uses the at least the approximate location todetermine a next movement of the MMU.
 17. The MMU as recited in claim11, wherein the sensing mechanism comprises: at least one proximitysensor for sensing objects near the MMU; a fiducial sensor for aligningthe holding portion with a cartridge holder of a media library; and aposition reading mechanism for determining a position of the MMU. 18.The MMU as recited in claim 11, wherein the drive mechanism comprises: amotor for providing rotation to each of a first drive wheel and a seconddrive wheel independently; the first and second drive wheels positionedopposite each other near the holding portion for propelling the MMU; anda swiveling caster wheel for allowing directional changes of the MMUpositioned to provide stability to the MMU.
 19. The MMU as recited inclaim 11, wherein the power source comprises a rechargeable battery, thebattery being adapted for recharging when the MMU is docked at a medialibrary.
 20. The MMU as recited in claim 11, further comprising acommunication device capable of communicating with the source medialibrary when the MMU is docked at the source media library, wherein thesource media library provides a location of the destination medialibrary during communicating with the MMU.